1. Field of Invention
This invention relates to a spreader bar for lifting sheets and a bow bar for supporting a covering for open-top trailers.
2. Discussion of the Prior Art and Technical Problems
One mode of transporting glass sheets between supplier and customer is by securing the glass sheets on collapsible frames or racks mounted on the bed of open-top trailers, e.g., trailers of the type taught in U.S. Pat. Nos. 2,969,284 and 3,066,924. The glass sheets are loaded on or unloaded from the frames by slings mounted on a spreader bar, e.g., of the type taught in U.S. Pat. Nos. 2,721,757; 3,193,880; 3,549,190; and 3,897,097. To assure the availability of a spreader bar, one is normally carried on the trailer. Providing each trailer with a spreader bar solves the problem of availability but poses problems of handling and/or storage. More particularly, the spreader bar normally weighs about 300 pounds (135 kilograms) and is handled by the driver of the truck. One person moving the bar on the trailer bed or floor in position to be connected to the hook of a crane is difficult and can pose a hazard. The prior art spreader bars are not easily stored when the trailer is empty and the trailer bed prepared for receiving return pay load. For example, the frames used for supporting the glass are collapsed and secured at the front end of the trailer to maximize available floor space. Because there are no provisions for storing the spreader bar, it remains on the trailer floor decreasing available floor space for the return pay load.
It would be advantageous, therefore, to provide a spreader bar that does not have the drawbacks of the prior art spreader bars.